The present invention relates broadly to a linear driver switch apparatus, and in particular to a bi-directional random-mode field effect transistor (FET) switch apparatus that is used for the control of microwave ferrite phase shifters and CRT deflection yokes.
The term switch or switching device is usually used to denote that class of device which is intended to function when an electrical circuit is energized or deenergized under normal operating conditions. In contrast a well known power device such as the circuit breaker has as one of its primary functions the interruption of short circuit currents. Although there are many different types of electric switches their application can be broadly classified into two major categories; power and signal.
In a power application, the function of a switch is to apply energy or remove energy from an electric load. A few examples of the low end of the power scale, includes wallswitches which are used in homes and offices for turning lights on and off; and, dial and push button switches which control power to electric ranges, washing machines and dishwashers. At the high power end of the scale are load-break switches and disconnect switches in power systems which operate at very high voltage.
For high power applications, the switches are required to carry a certain amount of continuous current without overheating when closed, and in the open position they must provide enough insulation to isolate the circuit electrically. The latter function is particularly important in high voltage circuit because it is the practice in the electrical industry to forbid people from working on electrical equipment unless it is isolated from the electrical supply system by a visible break in air. The present invention provides a means of connecting a high voltage source to a load.
The electronic drive for an S-band attenuator which was developed under an Air Force Program for the control of a high power mircrowave source, required a unipolar high voltage switching device for rapid reset. In order to allow the use of a second microwave input, the electronic drive had to be expanded to accommodate bi-directional switching, which doubled the driver size and weight.
The MOSFET quadrature switch apparatus was developed to accomplished bi-directional high voltage, high current switching with reduced size and weight. The configuration is capable of random-mode switching, and the improves recovery of energy from the inductive load, due to the use of a single high voltage power supply.